On Sun, Aug 20, 2017 at 04:06:46PM +0200, Paul B Mahol wrote: > On 8/19/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: > > On Sat, Aug 19, 2017 at 04:00:18PM +0200, Paul B Mahol wrote: > >> On 8/19/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: > >> > On Fri, Aug 18, 2017 at 06:21:56PM +0200, Paul B Mahol wrote: > >> >> On 8/18/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: > >> >> > Fixes: runtime error: shift exponent 4294967289 is too large for > >> >> > 32-bit > >> >> > type > >> >> > 'int' > >> >> > Fixes: 3030/clusterfuzz-testcase-minimized-4649809254285312 > >> >> > > >> >> > Found-by: continuous fuzzing process > >> >> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > >> >> > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > >> >> > --- > >> >> > libavcodec/pixlet.c | 2 +- > >> >> > 1 file changed, 1 insertion(+), 1 deletion(-) > >> >> > > >> >> > diff --git a/libavcodec/pixlet.c b/libavcodec/pixlet.c > >> >> > index 088226bdda..a9cfe085c9 100644 > >> >> > --- a/libavcodec/pixlet.c > >> >> > +++ b/libavcodec/pixlet.c > >> >> > @@ -262,7 +262,7 @@ static int read_high_coeffs(AVCodecContext > >> >> > *avctx, > >> >> > uint8_t *src, int16_t *dst, i > >> >> > > >> >> > flag = 0; > >> >> > > >> >> > - if (state * 4ULL > 0xFF || i >= size) > >> >> > + if ((uint64_t)state > 0xFF / 4 || i >= size) > >> >> > >> >> This is not exact same behaviour. > >> > > >> > no, it differs for a small number of cases that have one of the 2 > >> > most significant bits (of the 64 bits) set in state. > >> > I think this was a bug i introduced in a previous commit. > >> > > >> > If above change is not the correct thing to do, please elaborate. > >> > state is passed into ff_clz() later which has no deterministic > >> > behavior when these MSBs are set as ff_clz() uses unsigned and state > >> > is int64_t and unsigned can be 32 or 64bit. > >> > >> Only 32 bits matters for ff_clz() anyway. > > > > your reply is a bit terse. > > Does that mean you have no objections to the patch ? > > > > about ff_clz(), with 64bit unsigned a ff_clz(1) should return 63, the > > code looks like it expects 31 > > yes.
will apply the 2 patches thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I have often repented speaking, but never of holding my tongue. -- Xenocrates
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